Cam-grinding machine



March 10, 1931. J. c. SHAW ET AL CAM GRINDING MACHINE Filed July 2, 19 62 Sheets-Sheet 1 W Y N m% m m L a A YII L Y B A mm k 3 mm Mitch 10-,1931. c SHAW ETAL 4 1,796,125

' V cm GRINDING MACHINE Filed July 2. 1926 2 Sheets-Sheet 2' INVEN TOR.1A a yawn BY (240.40;

:rreu STATES.

PATENT OF F ICE fol-INv O. SHAW AND ROBERT D. SHAV, OF BROOKLYN, NEWYORK, ASSIGNORS TO KELLER MECHANICAL ENGINEEBINGOORPORATION, OFBROOKLYN, NEW YORK, A

CORPORATION, or NEW YORK CAM-GRINDING MACHINE Application filed July 2,

This improvement relates more particularly to a cam grinding machine,adapted for grinding cams in accordance with a master cam, thearrangement being such that various forms of cams may beaccuratelyground. It is well understood that cams ofvarious kinds are usually usedwithout hardening in order to maintain theoriginal accuracy of the camas cut, for hardening will almost invariably produce acertain amount ofdistortion. Heretofore machines capable of properly and accuratelygrinding hardened cams have not been'available and hence, various typesof cams used in machines subject to great'wear are required to bereplaced frequently.

The object, therefore, of our-improvement is to provide a cam grindingmachine, which will accurately and rapidly grind any ordinary type ofcam, such as cylinder or barrel cams, box cams, edgecams and facecams.It will also be understood that our cam grinding machine is adapted forgrinding an indefinite number of duplicate cams, in that the cams to beground are ground under the control of a master cam.

A further object of our improvement is to provide means for grindingcylindrical orv drum cams for any particular arrangement or movement ofthe cam roller. For instance, in some types of machines, the cam rollerfor cooperation with the groove of the drum cam is mounted on a shortradius arm, pivoted on an axis at right anglesto the axis of the drum,and hence swings in the arc of asmall circle in following the camgroove. Therefore, ifprovision is not made in the cutting and grindingof the cam groove for this circular arm movement, the cam rollerv willnot enter the cam track at certain points. Further-.

more, it has been customary in drum cams operating on a short radiusarm, as just stated, to use a spherical roller or-undercut the camgroove to such an extent as to provide only a point contact between theroller. and cam groove, but with our improvement the groove can be soground that a cylindrical follower roller an be used, thereby giving aline contact on the wall of the cam groove equalt-othe full width of theroller.

A further; object is to provide means for adjusting the relativepositions of the coacting members. For this purpose the cam rotatingsupports are preferably mounted on a work table which is provided withthe usual means for adjusting its position, thereby providing forrelative adjustment between the cam and the cam grinding element. Furthermore, to provide for grinding diflerent types of cams, such asbarrel and edge cams, two different arrangements of the cam rotatingelements are provided, both being mountedon the work table. To takeadvantage of this double arrangement, the grinding element and mastercam follower are mounted for transverse adjustment relative to the worktable so as. to bring them into cooperative relation with one or theother of the pairs of cam rotating members.

Furthermore, in some types of barrel and face cams, it is desirable togrind both side walls of the cam track or groove and, therefore, afurther object is to provide means for resiliently urging the camgrinding element either toward or from the work table, to therebyprovide for grinding the cam groove on both edges or sides.

One form of our improved cam grinding machine is illustrated in theaccompanying drawings, in which Fig. 1 shows the cam grindin machine inside elevation; Fig. 2 is a top plan view, the frame being partiallybroken; Fig. 3 is an end view of the pivotal support for the swingingarm, the frame being broken away; Fig. 4 is a sectional detail of thetracer or roller for the master cam; Fig. 5 is an enlarged side view ofthe guide bracket mounted on the work table; Fig. 6 is a top plan viewof the bracket shown in Fig. 5; Figs. 7, 8 and 9 are plan views of abarrel cam in different. positions for illustrating the swing of theradius arm carrying the cam roller; Fig. 10 illustrates another form ofcam roller support and Fig. 11 is an illustrative sectional view.

Referring to the drawings, it will be seen that the cam grinding machineelements are preferably supported on a base member 1, provided with alaterally extending bracket arm 2, which is fitted with verticallydisposed track ways 3, upon which the work table 4 is adaptedto slide,substantially as illustrated in Fig. 1, showing the present form of themachine. Any usual or preferred means may be employed for verticaladjustment of the work table 4 and for this pur-' pose, in the presentinstance, a rack 5 is secured to the edge of the work table 4, inposition to cooperate with a pinion 6, which is adapted to be rotatedfor adjusting the work table up or down, as may be desired. The usualclamping means (not shown) for holding the work table in adjustedposition may be employed. a i

The elements including arbors and gearing for supporting and rotatingthe master cam and the cam to be ground are mounted" on the face of thework table 4, as illustrated in Figs. 1 and 2. For grinding barrel cams,the respective arbors for the master-cam and cam to be ground extend atright angles to the face of the work table, while for grinding face oredge earns, the arbors extend parallel t0 the faceof the Work table. Inthe present machine the arbors 7 for barrel cams, which are adapted tobe rotated on axes at right angles to the face of the work table, aremounted in substantially-identical brackets or supports 8, which aresecured to the face of the work table by suitable bolts 9, as will beseen in Figs. 1 and 2. Each bracket or supportS is provided with a wormgear 10,

cooperating with a worm 11 mounted on a vertically disposed shaft 12,rotating in suitground, which is mounted upon the lower arbor 7 asillustrated in Fig. 1.

A somewhat similar arrangement is pro vided for'grinding face and edgecams, but for supporting the arbors parallel to the work table,shelf-like bracket supports 14 are preferably secured at the left sideof the work table 4, (Fig. 1) by suitable bolts '15, so that therespective arbors 16 thereof are vertically disposed and parallel to theface of the work 7 table. The shelf bracket supports 14 areprovided withworm gears 17. for rotating the respective arbors 16, said worm gearsbeing rotated by worms 18. The latter are geared by miter gears 19 witha vertically disposed shaft 20, corresponding to and in parallelrelation with the shaft 12 for rotating the barrel ca1narbors7. The.shaft 20 is rotatably supported in bearings 21 secured to the face ofthe work table 4, the arrangement being such that, when the shaft 20 isrotated, the arbors 16 will be rotated in unison. Likewise as for thearbors 7, by having the miter gears19, worms 18 and worm wheels 17 forboth arbors 16 of the same relative pitch, the latter will be rotatedsimultaneously and the master cam and'cam to be ground carried therebywill be rotated in synchronism, so that absolute accuracy as toreproduction is effected. v

In order to rotatethe respective pairs of arbors 7 and16, thecorresponding shafts 12 and 20 are provided with pulleys 22 and'23,secured to the upper ends thereof and adapt-'- ed to be'connected bymeans of a belt 24 with a pulley 25 mounted upon and rotated by a gear26. The large gear 26 is in mesh with a pinion 27 mounted upon the shaftof a motor 28, preferably secured to a boss projecting from the rearupper edge of the work table 4, by bolts 29, as will be seen in Fig. 2of the drawings. It will be understood that during operation of themachine only one shaft and set of arbors will be in operation at a timeand the belt 24 is accordingly placed on either pulley 22 or23'according to whether it is desired to grind barrel cams or edge cams.c

For movably supporting the grinding element or abrasive wheel and themaster follower roller, a swinging arm 30 is provided, the arm beinfulcrumed, at the left as shown in Fig. 1, on cone pivots 31, which aresupported on a floating member 32, the latter, in turn, being pivoted at33 to a carriage or slide block 34, as will be seen in Fig. 3. Thecarriage or slide 34 is mountedfon ways 35 extending laterally from ahorizontal bracket arm 36, supported upon or forming part of the mainframe 1, as'shown in Fig; 2. The usual lead screw 37 and hand wheel 38are provided for moving'the slide 34 along the ways 35, transverselyofthe work table 4. By this construction, it will be seen that theswinging arm 30 I may be'located so that its free end will lie incooperative relation with either the barrel cam arbors 7 or the edge camarbors 16, according towhich type of cam is to be ground.

The free end (at the right as shown in Fig. 1) of the swinging arm 30,is forked and the upper branch 39 is provided with a verticallyadjustable'spindle or shaft 40, carrying at its lower end a tracerroller 41, adapted to engage the cam track or-groove in the masterbarrel or cylinder cam A carried on the upper arbor 7, as shown inFig. 1. the tracer roller '41 is preferably tapered or cone shaped asshown in Fig. 4, so that by adjusting it up or down the depth ofgrinding contact of the grinding wheel can be regulated as desired. Thevertical position of the roller 41 may be adjusted in any suitablemanner and the spindle clamped in proper position by the bolt 42. Thevertical adjustment of the tracer roller 41, in the present instance, isaccomplished by means of a screw a (Fig. 4) .provided with; aflange 40bcooperating with a groove 40a in: the bearing block 40d.

Ian

Thus by turning the screw 40a the relative vertical position of theroller 41 can be regulated. The lower branch 43 of the swinging armcarries a rotatable spindle 44 the lower end of which carries anabrasive wheel 45 constituting the grinding element for grinding the camedge or groove such as the cam track or groove in the barrel cam B to beground, mounted upon the lower arbor 7,

as shown in Fig. 1. The barrel cam B, being the cam to be ground inconformity with the master cam, should be mounted on its arbor so thatthe cam track thereof will coincide,.in relative positioncircumferentially and otherwise with the cam track on the master cam Aon the upper arbor 7. It will be understood also that, in the presentinstance, the spindles and 44 carrying respectively the master followeror tracer roller and the grinding element are mounted in axial alignmentin a plane passing through the fulcrum pivot 31 of the swinging arm 30.In other words, a line passing through the axes of the master roller 41and the abrasive wheel will be parallel to the pivotal axis of theswinging arm 30, and also parallel to the face of the work table 4.

The upper end of the grinding wheel spindle 44 is provided with a pulley46 over which a belt 47 passes for rotating the grinding wheel 45 at thedesired speed. The belt 47, as shown in Figs. land 3, passes overdirection changing idler pulleys 48 to a pulley 49 mounted on the shaftof the motor 50.

The motor 50 is mounted on a shelf 51 on the rear upper edge of thebracket 30, being secured thereto by suitable bolts 52, as will be seeninFigs. 1 and 2.

Obviously, in grinding barrel and face cams, or other cams, having aslotor groove.

for operation upon a cam roller, it is desirable to provide for grindingboth side walls or edges of the cam grooves. Therefore, the masterroller and abrasive wheel should be resiliently movable so as to followthe edge to be ground. To provide for thus urging and moving theswinging arm 30, either toward or from the face of the work table 4,brackets 53 and 54 are secured by bolts 55 'to the swinging arm 30, aswill be seen in Figs. 1 and 2. A chain or cable 56 carrying a weight 57is adapted to be connected to the end 58 or 59 of the respectivebrackets 53, 54 to resiliently move the swinging arm 30, either towardor from the face of the work table 4. As wil be seen in Fig. 2,intermediate guide pulleys 60 and 61 are provided for changing thedirections of pull of the chain or cable 56, from vertical tohorizontal.

It will be understood that ordinary barrel or cylinder cams, such as maybe ground on our improved machine, are preferably designed for use witha cylindrical follower roller and, hence, arecut for and intended tocooperate with such follower rollers. Furthermore, these cylindricalfollower rollers are frequently mounted upon radius arms which areusually shorter or of a different length than the radius of the swingingarm 30, that is, the length between the pivot axis 31 and the axes ofthe master roller 41 and grinding wheel 45. For this reason, someprovision should be made for grinding the cam to conform both to themotion of the follower roller on the radius arm and to the changingangularity of the center line in reference to the radius of cam, asindicated 1n Fig. 11, otherwise the roller will not enter the groove atcertain positions of the follower arm. Therefore, in our improvement,provision is made for compelling the grind 111g element to follow anypredetermined path, corresponding to the path required to be followed bythe cam roller during the operation of the cam. For this purpose, theswinging arm 30, as previously pointed out, is pivotally mounted on andsupported by the bracket 32, which, as will be seen in F ig. 3, ispivoted at 33 to the slide 34.

It may be desirable to use the machine with the swinging arm 30 movableon a single pivot, and for this purpose the slide 34, in the presentinstance, is provided with an upwardly projecting lug 62, having an eyethrough which a locking bolt 63 may be passed into a socket at 64, inthe floating bracket 32, to thereby lock it in predetermined position,preferably at right angles to the face of the slide 34, as seen in Fig3. thus pivoting the arm 30 on the pivots 31 only. A similar lug 65 isprovided on the upper end of the floating bracket 32, through which thelocking bolt 63 may be passed into a socket at 66 for locking theswingii'ig arm 30 to the floating bracket 32 so that it sivings from thepivots 33, thereby providing for changing the pivotal relation of thefulcrum of the arm to the tracer roller and grinding element. Obviously,for swinging movement of the arm on a single pivot, the locking bolt 63should be placed only in one or the other of the sockets 64, 66,according to the pivotal action required.

lVhen, however, the fulcrum of the swingmg arm 30 is to remain freelyfloating, it will be necessary, as previously indicated, to guide thefree or outer end of the arm, as it is moved toward or from the worktable 4 under the guidance of the master cam A, which will move theswinging arm by means of the master follower roller 41. For thispurpose, an angle bracket 67 (see Figs. 5 and 6) is mounted on the worktable 4 by bolts 68 which preferably pass through elongated holes 69, soas to provide for lateral adjustment of the bracket. The outwardlyextending angle portion 70 of the bracket is faced off and carriesanother angle bracket 71 se' cured thereto by bolts 7 2 which likewisepass through elongated holes .toprovide for positioning the bracket 71.The upper horizontal face 73 of the bracket 71 is adapted to support aplate 74 which may be adjustably secured thereto by clamps 7 5 andadjusting bolts 76, as indicated'in Figs. 5 and 6. The plate 74, whenmounted on the bracket, is provided with a closed slot 7 7 which may bestraight, as shown in Fig. 2, ,or arc shaped on any de'sired'radius, asindicated at 78 in Fig. 6. As will be seen in Figs. 1 and 2, the slot 77 in the plate 74 is adapted to cooperate with a roller 79 carried onthe upper end of the spindle 40s, the arrangement being such that theslot 77 and roller 79 in cooperation with the tracer roller 41 followingthe master cam groove will guide the movement of the free end of theswinging arm 30, to conform to the desired path of the follower. In thismanner, it will be seen that if the cam groove has been rough-cut to theproper shape of a cam to be ground to conform to the requirements of acylindrical follower roller on a given radius, in the machine, for whichthe cam is designed; then, with the master roller 41 following themaster cam, and the guide roller 7 9 following a curved slot 7 8 of thedesired radius, as shown in Fig. 6, in the plate"? 4, the cam to beground will be accurately ground to the desired shape and dimensionssuch as to properly fit and operate in conjunction with a cylindricalfollower roller (see Fig. 11).

To illustrate the desirability of this floating mounting of the swingingarm 80, and the action of the plate 74, Figs. 7, 8 and 9 'of thedrawings are inserted to illustrate a barrel cam 80, provided with atrack. or groove 81 with which the follower roller 82 cooperates. Itwill be seen, however, that in this particular arrangement, the roller82 is mounted on a relatively short follower arm 88 pivoted at 84,thereby compelling the roller 82, as it follows the cam groove, to swingthrough the arc of the circle, represented by dotted lines at 85, inpassing from one end 86 of the cam to the other end-87 thereof.Obviously, if the edgesor side-walls of the cam groove 8186-87 wereground with the swinging arm 30 of the cam grinder on a fixed pivot, thecam follower roller 82 would not enter the cam groove at certainpositions, because the radius of the arm 30 is much longer than theradius arm 83 for the follower roller 82. Furthermore, it will beobvious from Fig. 11 that, with a cylindrical follower roller 82, thetrack or groove in the barrelcam must be cut and ground with its sidewalls at varying angles to the radius of cam barrel for the axis of thefollower roller 82 comes into line with the radius only at one pointduring the swing of the follower arm 83 in either direction from thecen-- ter, this point being represented by the cen-- tral full lineposition of the roller 82 in Fig.

follower roller 82, as it swings onthe' follower'arm 83, as representedin Figs. 7 to 9 and 11.

On the other hand, if the barrel cam 88, as shown in Fig 10, is intendedto operate a cam roller 89 slidably novable in a straight line, parallelto the axis of rotation of the cam, as, for instance, when guided byare-- ciprocating sliding bar 90, the tracking of the roller 89 wouldbe'imperfect if ground with the swinging arm, unless provision is madefor a corresponding, parallel to the axis, movement of the grindingelement.

Hence, by providing the plate 74 with a straight slot 77, as shown inFig, 2, the latter, by cooperating with the roller 79, will so guide thegrinding wheel 45, as the master roller 41 follows the master cam, thatthe cam to be ground (B) will conform accurately to the type of the camrepresented in Fig. 10.

The operation of our improved cam grindmachine can be readily understoodfrom the description given inconnectionwith the drawings and itwill beseen thatwhen itis desired to grind a cylinder or barrel cam, the slide34 is moved, by means of the hand wheel 38, to the. position shown inFigs. 1 and 2, so that the axialline of the master roller 41 passesthrough the axis of'the upper arbor 7, to which the master cam A issecured, and the same axial line, which also passes through the grindingwheel 45, passes through the axis of the lower arbor 7, upon which E,the cam to be ground, is mounted. The master cam andthe cam to be groundshould be mounted in the same relative, position circumferentially, sothat when the shaft 12 is rotated, the Care to be ground will be rotatedin synchronism with the master cam, the cams being rotated by therespectiv worms 11 and worm gears 10. 1

As previously pointed out, it will be understood that if the barrel camB,.to beground,"

is intended for use with a cam roller, supported'for use upon a radiusarm, as illustrated in Figs. 7 to 9, the plate 7 4 is brought into useand provided with the desired arcuateslot 78; the plate 7 4 beingmounted upon the bracket 71 for cooperation with the guide roller 79.

As previously pointed out, the walls or edges of the cam-groove areground separately. In the operation of grinding the inner wall or edgeof the cam to be ground, as shown in Fig. 2, the swlnging arm 30 shouldbe urged toward the work table 4 and, for

weight 57 will tend to pull the arm 30 inward,

so that the master roller 41 will follow the edge 91. hen it is desiredto grind the outer wall or edge of the cam, the chain 56 is secured tothe heel: end 58 of the bracket 53, thereby urging the swinging arm 30outward or away from the work table 4, so that the master roller willfollow the edge 92.

It wiil be understood that the motor 28, through the belt 24, willrotate the shaft..12

and thereby rotate the master cam and cam to be ground in synchronism.while the motor 50, through the belt ll, will rotate the grindingelement or abrasive wheel 45 for grindingthe walls or edges of the cam Bin conformity with the master cam under the guidance of the masterroller 41. It will also be understood that after the roller 41 andabrasive wheel 45 have been properly adjusted as to their relativept-sition on the axial line thereof, their relation to the face or wallof the master cam and cam to be ground can be adjusted by moving thework table 1 vertically, either up or down, by means of the rack andpinion 56. Such adjustment can be made at the start of the grindingoperation to place the grinding wheel 45 properly in the groove of thebarrel cam, but the position of the grinding face of the grinding wheelis determined by adjusting the taper tracer wheel 41 up or down by meansof the screw 40a. This taper tracer roller has other advantages.Forinstance, it permits adjustments for varying the diameter of thegrinding wheel thus permittingthe grinding of cams with different widthsof grooves from the same master cam. Also it permits taking a roughingcut and a finishing cut.

When it is desired to grind face or edge cams, the slide 34 will bemoved toward the right, as viewed in Figs. 1 and 2, by the hand wheel38, until the axial line of the roller 41 and grinding wheel 45 is inthe plane of the arbors 16, that is, in a plane at right angles to thework table 4. In this position,

the master roller ll will be in position to cooperate with the mastercam G mounted on the upper arbor 16, while the abrasive wheel 7 45 willbe in position to grind the edge of the cam D, which is mounted upon thelower arbor 16, as indicated in Figs. 1 and 2. During this operation,the shaft 20 should be rotated so as to rotate the worms 18 and therebyrotate the arbors 16 in unison, and for this purpose, the belt24 will beswung over to the dotted line position as shown in Fig. 2, so as toengage the pulley 23.

In grinding the groove or track in barrel or face cams it will beunderstood that it is preferable to grind the walls of the cam groovewith a grinding wheel having substantially the diameter of the followerroller r to be used therein, but the wheel should'not be large enough tofill the groove and touch both walls.

\Vhile we have shown and described the preferred form of our improvedcam grinding machine, it will be understood that we do not wish to belimited to the construction shown for various modifications in thespecii'ic details thereof may be made without departing from the spiritand scope of the invention.

Vie claim 1. A cam grinding machine comprising a work table, a pair ofrotatable elements on said table for grinding barrel cams, one of saidelements supporting a master cam and the other the cam to be ground, asecond pair of rotatable elements mounted on said table for grindingedge cams, one of the last named elements supporting a master cam andthe other the cam to be ground, a swinging arm pivotally mounted andcarrying a tracer roller and an abrasive wheel for cooperationrespectively with the master cam and cam to be ground of one pair or ofthe other of said rotatable elements, a slide member upon which saidswinging arm is pivotally mounted and means for moving said slide memberto bring the master roller and abrasive wheel into position to cooperatewith the cams of one or the other of said pairs of elements.

2. The cam grinding machine as claimed in claim 1, in which saidswinging arm is mounted on a floating pivot member pivotally supportedon said slide and a cooperating slot and roller are provided for guidingthe free end of said swinging arm, when in position for grinding barrelcams.

3. The cam grinding machine as claimed in claim 1, in which said worktable is provided with feed means adapted for adjusting the positionthereof and hence of the respective pairs of cam elements axially of andrelative to the master roller and abrasive wheel carried by saidswinging arm, so as to vary the position of the face of the grindingwheel relative to and transversely of the face of the cam being ground.

4. The cam grinding machine as claimed in claim 1, in which means isprovided for resiliently urging said swinging arm toward said work tablefor grinding one face of a cam and away from said table for grinding theother face of said cam.

5. The cam grinding machine as claimed in claim 1, in which a motormounted on said work table is provided for rotating one or the other ofsaid pairs of rotatable elements, substantially as described.

6. A cam grinding machine comprising a support for a master cam, asupport for the cam to be ground, means for rotating said cam supportsin unison, a movable member carrying a tracer roller and an abrasivewheel for cooperation respectively with the master cam and the face ofthe cam to be ground and means controlling movement of said movablemember transversely of the axes of-saidrotating supports While saidtracer roller follows themaster cam, including a floating pivot for saidmovable member and a guide slot and roller for guiding said movablemem-1' her transversely of said rotatable cam support.

" 7 A cam grinding machine comprising a rotatable support for a mastercam, a rotatable support for the cam to be ground, means for rotatingsaid cam supports in synchronism, movable means supporting a tracerroller and a rotating grinding Wheel for cooperation respectively withsaid master cam and the cam to be ground, said tracer roller and thegrinding Wheel being located in axial alignment in a plane at rightangles to the direction of motion of said movable means, a cone-shapedtracer roller mounted on said movable supporting means and means foradjusting the position of the latter in an axial direction to adjust theposition of the grinding Wheel toward and from the face of th cam to beground.

, JOHN C. SHAW.

ROBERT D. SHAW:

